This study is concerned with electrophysiologic observation of the canine larynx to record muscle activity in each of the intrinsic and extrinsic laryngeal muscles. Results of these experiments are as follows: All the intrinsic and extrinsic laryngeal muscles except the posterior cricoarytenoid and the cricothyroid muscles did not discharge regularly during quiet respiration without anesthesia. Posterior cricoarytenoid and cricoarytenoid tended to discharge continuously during quiet respiration without anesthesia, but inspiratory discharge of posterior cricoarytenoid was observed during vigorous respiration. The sternohyoid along with the sternothyroid did not discharge regularly during normal (quiet) respiration without anesthesia, as decribed by other investigators, but were observed to discharge irregularly during the inspiratory phase of severe dyspnea. Our research goal for the next year is finding out the other muscles or nerves to be used as substitute for instrinsic laryngeal muscles or recurrent laryngeal nerve. BIBLIOGRAPHIC REFERENCES: Satoh, I, Harvey, JE, Ogura, JH: Impairment of function of the intrinsic laryngeal muscles after regeneration of the recurrent laryngeal nerve. Laryngoscope, 84:1:53-66, January, 1974. Satoh, I, Harvey, JE, Ogura, JH: Regeneration of the laryngeal sensory nerves. Laryngoscope 84:67-77, January, 1974.